Method of preparing light-sensitive photographic material with manganese dioxide layer

ABSTRACT

A COOLOIDAL MANGANESE DIOXIDE DISPERSION OBTAINED BY THE REACTION OF POTASSIUM PERMANGANATE WITH A CHEMICALLY MODIFIED GELATIN IS PARTICULARLY USEFUL IN A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL. THE GELATIN IS TREATED WITH A COMPOUND CAPABLE OF REACTING WITH THE AMINO GROUP OF THE GELATIN, E.G. SULFONYL CHLORIDES, CARBOXYLIC ACID CHLORIDES, ACID ANHYDRIDES, ISOCYANATES AND 1,4-DIKETONES. UNDESIRED HALATION OR IRRADIATION CAN BE EFFECTIVELY PREVENTED.

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[ METHOD OF PREPARING [56] References Cited LIGHT-SENSITIVE PHOTOGRAPHICUNITED STATES PATENTS MATERIAL WITH MANGANESE DIOXIDE 2,614,928 10/1952Yutzy et a1 96/94 R LAYER 3,630,739 12 1971 Hine 96/84 R Inventors:Tomio N j Masa 3,332,792 7/1967 Mackey 96/84 R y shono, shinobuKorematsu, 2,095,018 10/1937 wilmanns et a]. 96/84 R all of Tokyo, JapanPrimary Exammer-Ronald H. Smith [73] Assignee: Konishiroku PhotoIndustry Co., Atmmey"waters Rodm Schwartz Nlsse Ltd.

[57] ABSTRACT Filedi 1971 A colloidal manganese dioxide dispersionobtained by [2 APPL NO; 128 167 the reaction of potassium permanganatewith a chemically modified gelatin is particularly useful in alightsensitive photographic material. The gelatin is treated ForeignApplication ly Data with a compound capable of reacting with the aminoMar. 26, 1970 Japan 45/24833 group of the gelatin, e.g. sulfonylchlorides, carboxylic Mar. 26, 1970 Japan 45/24834 acid chlorides, acidanhydrides, isocyanates and 1,4-

diketones. Undesired halation or irradiation can be ef- [52] US. Cl.117/333, 96/84 R, 117/34, fectively prevented.

252/300 2 C N D 511 1m. 01 cosc 1/84 lam, "mugs [58] Field of Search96/84; 117/333,

METHOD OF PREPARING LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL WITH MANGANESEDIOXIDE LAYER This invention relates to a light-sensitive photographicmaterial in which a colloidal manganese dioxide pigment is used. Moreparticularly, the invention pertains to a light-sensitive photographicmaterial in which a colloidal pigmentary manganese dioxide is used whichis prepared by reacting potassium permanganate with a modified gelatin.

Colloidal manganese dioxide dispersions are useful as a pigment for theantihalation of light-sensitive photographic materials. Accordingly,they have been thoroughly studied, and there have been already proposedprocesses for preparing them by reacting gelatin, gum arabic, polyvinylalcohol, starch ether, a mixture of gelatin and citric acid, or the likewith potassium permanganate. In carrying out these processes inpractice, however, there are encountered various difficulties. Forexample, in the processes using gelatin, great increase in the viscosityof the reaction liquids is brought about during the course of thereaction. Further the resulting colloids have migrated, in most cases,with rubbery of film-like lumps. In the processes using material otherthan gelatin, the resulting colloids are unstable, and therefore fail togive a dispersion having a well controlled concentration. Further thesecolloids have migrated with lump-like substances, and stains are lefteven after bleaching in the fixing step. Thus, the colloids preparedaccording to the above-mentioned known processes have not been suitablefor the antihalation of light-sensitive photographic materials.

The object of the present invention is to provide a light-sensitivephotographic material in which a colloidal manganese dioxide dispersionis used which is free from such drawbacks as mentioned above.

As the result of extensive studies, we have found that when a modifiedgelatin is used, it is possible to obtain a colloidal manganese dioxidedispersion suitable for use as the antihalation layer of alight-sensitive photographic material.

As the gelatin to be modified, there may be used ordinary photographicgelatins such as those made from ossein or hide, and, for themodification of the gelatin, there may be used a compound which iscapable of reacting with the amino group of the gelatin.

Examples of compounds suitable for the modification of gelatin which maybe used in the present invention are enumerated below.

Sulfonyl chlorides:

. Benzenesulfonyl chloride p-Methoxybenzenesulfonyl chloridep-Phenoxybenzenesulfonyl chloride p-Bromobenzenesulfonyl chloridep-Toluenesulfonyl chloride m-Nitrobenzenesulfonyl chlorideNaphthalene-B-sulfonyl chloride p-Chlorobenzenesulfonyl chloridem-Carboxybenzenesulfonyl chloride 10. 2-Amino-5-methylbenzenesulfonylchloride Carboxylic acid chlorides:

ll. Phthalyl chloride 12. p-Nitrobenzoyl chloride 13. Benzyl chloride14. F uroyl chloride 15. Methacryl chloride Acid anhydrides:

l6. Phthalic anhydride l7. Benzoic anhydride l8. Succinic anhydride 19.Maleic anhydride 20. Itaconic anhydride 2l. Methacrylic anhydrideIsocyanates:

22. Phenyl isocyanate 23. p-Bromophenyl isocyanate 24. p-Chlorophenylisocyanate 25. p-Nitrophenyl isocyanate 26. a-Naphthyl isocyanate 27.B-Naphthyl isocyanate 1 ,4-Diketones:

28. Acetonylacetone 29. Dimethyl acetonylacetone 30. Diethyldiacetylsuccinate Modification of the gelatin by use of the abovementionedcompounds may be carried out according to the method disclosed in U.S.Pat. No. 2,614,928. Particularly, phthalized gelatins are commerciallyavailable.

When a chemically modified gelatin is sued in the reduction of potassiumpermanganate, a colloidal manganese dioxide dispersion is obtained quitestably without fluctuation in concentration and further withoutdeterio-rating any photographic properties.

The advantages attained in the case where a colloidal manganese dioxidedispersion is prepared by use of a modified gelatin are mentioned belowwith reference to the case where potassium permanganate and gelatin arereacted with each other according to the method disclosed inKolloid-Zeitschrift, Vol. 19, page 241 (1916) and then the resultingreaction liquid is stabilized by addition of gelatin and manganesesulfate.

In reacting with potassium permanganate, a modified gelatin and anordinary photographic gelatin greatly differ from each other in thedegree of viscosity increase immediately after mixing of the twocompounds.

In the case when an ordinary photographic gelatin is used, a markedviscosity increase is observed immediately after mixing with potassiumpermanganate. Particularly when the two compounds are reacted with eachother at high concentrations, the whole reaction system is brought intothe form of a lump which makes the stirring thereof difficult, so thatthe reaction is heterogeneous making it impossible to obtain ahomogeneous colloid system even when a stabilization operation iseffected subsequently.

On the other hand, in the case when a modified gelatin is used in placeof the ordinary photographic gelatin in entirely the same reactionsystem as above, the viscosity increase brought about by mixing withpotassium permanganate is so slight that the reaction system issubstantially in the form of a liquid, and therefore, the reaction canbe effected sufficiently homogeneously by weak stirring to make itpossible to obtain a stable colloidal manganese dioxide dispersion.

Such difference becomes marked when the compounds used are high inconcentration, and no homogeneous colloid system can be obtained unlessa modified gelatin is used. The modified gelatin according to thepresent invention brings about no detrimental effect not only at thetime of reaction with potassium pennanganate, but also in variousoperations carried out for the purpose of stabilizing. and desalting ofthe photographic emulsion and in the case where the resulting colloidalmanganese dioxide dispersion is used to form a photographic antihalationlayer. Moreover, the modified gelatin has many more advantages than inthe case of ordinary gelatin. That is, in carrying out such desaltingoperation that a photographic emulsion is acidified to form acolloid-binder agglomerate, which is then washed with water andredispersed in a solution high in pH value, as is well known in the caseof an ordinary photographic emulsion, the use of the modified gelatinresults in such advantage that the operation can be effected withoutusing any other reagent for precipitation. Further, in other desaltingoperations, e.g. in the case where a photographic emulsion is cold-set,waterwashed and then redispersed, the use of the modified gelatinresults in such advantage that it swells to a proper extent to make thedissolution thereof easy. In addition, the formation of film-likeinsoluble material which is frequently experienced can be alleviated, sothat there are brought about no such drawbacks that insoluble materialclog the filter used for the removal thereof or adhere, without beingfiltered, to the coated material.

The process of the present invention is effectively applicable to thecase where potassium permanganate is reacted not only with the modifiedgelatine alone but in combination with citric acid, polyvinyl alcohol,gum arabic, glucose, etc. and with other reducing agents and protectivecolloids. The modified gelatin may be used not only in theabove-mentioned reaction but also in place of gelatin used forstabilization and coating. Further, the resulting colloidal manganesedioxide dispersion may be incorporated, for coating or the like purpose,with a coating aid, a hardener, a colloid stabilizer, a dye, etc. Thecolloidal dispersion is dark brown and scarcely varies in color evenwhen it is allowed to stand or is coated on a substrate. In view of thevarious characteristics as mentioned above, it will be easily understoodthat the thus obtained colloidal dispersion is useful as a photographicantihalation layer, a filter layer, an anti-irradiation layer, etc.

The following examples are the preferred embodiments of the presentinvention, but needless to say the present invention is not limited tothese examples, and various modifications are possible within the scopeof the invention.

EXAMPLE 1 A solution of 100 g. of photographic gelatin in 50 cc. ofwater was adjusted to pH 9.5 by addition of caustic soda. To thissolution was added a solution of 5 g. of phenyl isocyanate in 40 cc. ofacetone, and the resulting mixed solution was stirred at 60C. forminutes.

The reaction liquid was adjusted to pH 6.0, stirred at 45C. and thenmixed with 500 cc. of 3.5% potassium permanganate. After the mixing, theliquid gradually discolored from magenta color to dark brown. Aftercomplete discoloration, the liquid was charged with a solution of g. ofmanganese chloride and 50 g. of photographic gelatin in 500 cc. ofwater, and then allowed to stand for 30 minutes. Subsequently, theliquid was cooled, allowed to stand overnight in a refrigerator kept at2C., redispersed and then washed with running water for 1 hour to obtaina colloidal manganese dioxide dispersion.

The thus obtained dispersion was incorporated with gelatin (forcoating), a hardener, a plasticizer and a coating aid, and then coatedon a cellulose triacetate base to a dry thickness of 6 p, whereby thefilm showed excellent properties as an antihalation layer fororthosensitized photographic materials usable in the graphic arts.

For comparison, the same procedures as above were repeated except thatthe gelatin was not modified with phenyl isocyanate. In this case, theliquid greatly increased in viscosity at the time when it was mixed withpotassium permanganate, so that the stirring of the liquid becamedifficult. Further, the resulting colloidal dispersion migrated withinsoluble agglomerates and hence was high in viscosity, and the coatingof the dispersion was difficult.

EXAMPLE 2 The same gelatin solution as in Example 1 was adjusted to pH10. To this solution was added an acetone solution containing 15 g. ofphthalic anhydride, and the resulting mixed solution was treated for 30minutes. Thereafter, the reaction liquid was adjusted to pH 6.0, andthen mixed with 8 g. of glucose and 700 cc. of 3.5% potassiumpermanganate. Subsequently, the same operation as in Example 1 waseffected to obtain an excellent colloidal manganese dioxide dispersion,which did not clog a 350 mesh filter.

The thus obtained dispersion was coated on a cellulose triacetate basein the same manner as in Example 1, whereby an excellent antihalationlayer was formed. Example 3 Example 1 was repeated except that each of10 g. of p-toluenesulfonyl chloride, 10 g. of benzoyl chloride and 15 g.of acetonylacetone was used in place of the phenyl isocyanate to preparea colloidal manganese dioxide dispersion. The thus prepared dispersionwas coated on a triacetate base in the same manner as in Example 1,whereby an excellent antihalation layer was formed.

What we claim is:

1. A method of producing a light-sensitive photographic materialcomprising reacting gelatin with a member selected from the groupconsisting of sulfonyl chlorides, carboxylic acid halides, carboxylicacid anhydrides, aromatic isocyanates, and l-4 diketones to form amodified gelatin, reacting potassium permanganate in an aqueous solutionwith the modified gelatin to form a stable colloidal manganese dioxidedispersion and applying said dispersion as an anti-halation layer on alight sensitive photographic material.

2. A method as claimed in claim 1 comprising coating a transparent basesupport with the dispersion before application to said photographicmaterial.

